Dong Hyun Lee1, Byung Soon Chun1, Yoong Lee1, Ah-Hyung Alissa Park2, Sang Done Kim3, John R. Grace4, and Norman Epstein4. (1) Department of Chemical Engineering, Sungkyunkwan university, 300 chunchun, jangan, Suwon, South Korea, (2) Earth and Environmental Engineering and Chemical Engineering, Columbia University, 918 S.W. Mudd Hall, MC 4711, 500 W. 120th Street, New York, NY 10027, (3) Department of Chemical and Biomolecular Engineering & Energy and Environment Research Center, Korea Advanced Institute of Science and Technology, 373-1 Guseung, Yuseong, Daejeon, South Korea, (4) Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Room 218, Vancouver, BC V6T 1Z3, Canada
The axial particle concentrations before and after layer inversion were measured in two-phase (liquid-solid) and three-phase (gas-liquid-solid) fluidized beds. The experiments were carried out in a using a half-tube acrylic column (210-mm diameter) having a height of 1.8 m. 3.2-mm polymer beads (1,280 kg/m3) and 0.385-mm glass beads (2,500 kg/m3) were selected as a binary solid mixture of lighter/larger particles and denser/smaller particles, respectively. Water was the continuous phase in both cases, whereas air is the dispersed phase for the three-phase system. The axial particle concentration distribution was determined by measuring the axial pressure gradient and sampling the denser/smaller particles along the bed height. In three-phase fluidized beds of the particle mixture, the total solid phase holdup decreased with increasing liquid velocity, but the gas phase holdup remained the same at a given superficial gas velocity. After air injection into the two-phase fluidized bed of the binary mixtures, there were initial contractions of the upper layer of the bed above the liquid velocity corresponding to the inversion point.